“Securities and Exchange Commission Chairman Mary Schapiro said Tuesday that regulators haven’t yet found evidence of a “single cause” for last week’s market plunge, as federal regulators established a joint advisory committee to look into the causes of the drop.”

Markets dropped close to a 1000 points in less then 30 minutes, no one has a clue how…

“Investigators also haven’t found any unusual trading in Proctor & Gamble Co.’s shares, which tumbled during the market chaos. They also haven’t found evidence of hackers or terrorists.”

“The SEC also is considering a ban on “stub quoting,” a practice of offering pennies for valuable stocks; placing limits or “collars” on aggressively priced orders; and instituting “time-out” mechanisms that could be applied market-wide or to individual stocks, Ms. Schapiro said.”

There is also the wildly reported possibly of a “Fat finger” – someone who pushed an extra zero on a sell order…